Abstract: A resonator is disclosed which includes: a sleeve insert and an outer duct sealingly coupled to the sleeve insert. The sleeve insert has a wall with a first aperture in the wall at a first axial distance, a second aperture in the wall at a second axial distance, and a rib extending radially outwardly with the rib located between the first and second apertures. The outer duct sealingly couples to the sleeve insert proximate first and second ends of the inner sleeve and at the rib. The sleeve insert and the outer duct are formed of plastic materials which are coupled by welding or via o-rings placed on the sleeve insert. Cavities, in the vicinity of the apertures, are formed in the outer duct. The cavities, which are fluidly coupled to the sleeve insert via the apertures, attenuate noise.

Abstract: A method for manufacturing a resonator is disclosed in which a sleeve insert is placed into a fixture within a blow molding apparatus. The sleeve insert has a wall with a first plurality of apertures in the wall at a first axial distance and a second plurality of apertures in the wall at a second axial distance. A parison is slid over the sleeve insert; the mold is clamped over the parison causing the parison to press into the sleeve insert at three locations: near the ends of the sleeve insert and at a location between the pluralities of apertures; and air is blown into the sleeve insert, via a blow pin, to expand the parison into the walls of the mold to form cavities proximate the first and second pluralities of aperatures. After cooling, the mold opens to release the newly formed resonator.